I had the opportunity to write the cover article (Semiconductor Trends in Sub-6 GHz 5G Networks) for the June 2020 issue of Microwave Journal. As always, a great issue of Microwave Journal, so thanks to the Microwave Journal editorial team and please take a look at the magazine. With all the uncertainty navigating through this global COVID-19 pandemic, it’s reassuring to know that the people at Microwave Journal continue to bring the latest information to our industry.
The millimeter wave (FR2) portion of 5G networks has gotten a lot of attention, but sub-6 GHz 5G networks present some interesting challenges and opportunities. While the millimeter wave bands offer significant amounts of bandwidth, the signal propagation characteristics of these bands will limit how broadly operators deploy millimeter wave base stations, at least initially. The sub-6 GHz bands, especially as operators implement the 600/700 MHz “digital dividend” frequency bands for 5G, will have superior building penetration and footprint characteristics, but the available bandwidth pales in comparison to the multi-GHz bandwidth available in some of the millimeter bands. The article shows my latest thoughts on the frequency share for sub-6 GHz and millimeter wave 5G network deployments.
In addition to differences in signal propagation characteristics, the two 5G frequency bands will have different architecture and technology profiles. At millimeter wave frequency ranges, the 5G networks will likely feature a massive MIMO antenna, with GaN and silicon (either RF CMOS or SiGe BiCMOS) the leading contenders for the final RF output power stage. In addition to the output stage, the compound semiconductor content is likely to push a little bit farther away from the antenna in a hybrid beamformer configuration for the millimeter wave networks.
The situation in the sub-6 GHz 5G networks is substantially different. While the base station deployments are trending toward massive MIMO antennas, conventional antenna configurations (up to 8T/8R) are still prevalent. In these deployments, you are much more likely to see digital beamforming with silicon pushing out very close to the antenna. The other big difference is that LDMOS becomes very competitive with GaN as an RF power technology. The article lists some thoughts about the relative advantages of GaN and LDMOS, along with a forecast for the market share of technologies in the sub-6 GHz portion of 5G networks.
So, 5G networks are here to stay, but the big question becomes how your company understands and capitalizes on these emerging opportunities. If you have any questions about the article or my thoughts on how the 5G network will deploy in the future and where the opportunities will exist, please contact me. I hope everyone stays safe and thanks, again to Microwave Journal!
-Eric